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Sensitive and selective quantification of specific analytes is of great significance in analytical and environmental sciences, as well as in the food industry. Herein, we report the design, synthesis, characterization, and application of a responsive ruthenium(II) complex probe, Ru-azo, for phosphorescence and time-gated luminescence (TGL) detection of bisulfite, an important additive in the food industry. Upon a specific nucleophilic addition reaction between bisulfite and the azo group of Ru-azo, a new ruthenium(II) complex, Ru-SO3, was obtained, which resulted in a remarkable increase in phosphorescence intensity, allowing the bisulfite detection to be achieved. In addition, long-lived emissions of Ru-azo (τ = 258 ns) and Ru-SO3 (τ = 261 ns) also enabled the TGL detection of bisulfite in autofluorescence-rich food samples. Through theoretical computations, the photoinduced electron transfer (PET) process within the ruthenium(II) complex was validated, which unveiled the rationality of the luminescence "off-on" response of Ru-azo to bisulfite. The probe showed advantages of good water solubility, and high sensitivity, selectivity and accuracy for responding to bisulfite, facilitating its application in phosphorescence and TGL detection of bisulfite in aqueous and food samples. [ABSTRACT FROM AUTHOR]

Abstract: Development of novel bioanalytical methods for monitoring of H2S is key toward understanding the physiological and pathological functions of this gasotransmitter in live organisms. A ruthenium(II)‐complex‐based luminescence probe, Ru‐MDB (MDB: 4’‐methyl‐[2,2’‐bipyridine]‐4‐yl)methyl 2‐((2,4‐dinitrophenyl)thio)benzoate), was developed by introducing a new H2S responsive masking moiety to a red‐emitting RuII luminophore. Cleavage of this masking group by a H2S‐triggered reaction leads to a luminescence “off–on” response. The long‐lived emissions of Ru‐MDB and its reaction product with H2S allowed quantitative detection of H2S in autofluorescence‐rich human sera and adult zebrafish organs using the time‐gated luminescence mode. Ru‐MDB exhibits red emission, a large Stokes shift, high specificity and sensitivity for H2S detection, and low cytotoxicity, which enables imaging and flow cytometry analysis of lysosomal H2S generation in live inflamed cells under drug stimulation. Monitoring of H2S in live Daphnia magna, zebrafish embryos, adult zebrafish, and mice, was conducted by in vivo imaging using Ru‐MDB as a probe. [ABSTRACT FROM AUTHOR]

We report a novel ruthenium(II) complex-based long-lived and two-photon luminescence probe, Ru-NO 2 , for dynamic monitoring of GSTs fluxes in the process of drug-induced liver injury (DILI). Ru-NO 2 shows weak luminescence due to the strong photo-induced electron transfer (PET) process from the Ru(II) center to the electron-withdrawing 3,4-dinitrobenzene (DNB) group. As a result of the specific nucleophilic aromatic substitution triggered by GSTs in the presence of reduced glutathione (GSH), the 4-nitro group of Ru-NO 2 is substituted by GSH to form strongly emissive Ru-SG. Ru-NO 2 shows high selectivity and sensitivity for responding to GSTs. Notably, one- and two-photon luminescence imaging experiments were conducted to visualize GSTs in living cells and mouse tissues. In addition, Ru-NO 2 was applied for background-free time-gated luminescence (TGL) detection and luminescence imaging analysis of GSTs in DILI mouse sera and liver tissues, which showed that GSTs level in sera significantly increased accompanied by the decrease in liver in the DILI process, revealing the possible potential of the probe as an effective tool for clinical diagnosis and treatment monitoring of DILI. [Display omitted] • A novel Ru(II)-complex-based long-lived two-photon luminescence probe for GSTs detection. • TGL analysis of GSTs in biosamples without autofluorescence interference. • Visualization of GSTs in vitro and in vivo by one-/two-photon luminescence imaging. • Monitoring GSTs fluxes in the process of DILI by TGL and TP luminescence analysis. [ABSTRACT FROM AUTHOR]